Engine starter gearing



1966 J. J. DIGBY ENGINE STARTER GEARING Filed Dec. 16, 1964 aw Mn mw Mm wi QMF N Qw wh QM sh wwmv INVENTOR. 2711/7266 United States Patent O 3,263,509 ENGINE STARTER GEARING James J. Digby, Elmira, N.Y., assignor to The Bendix Corporation, Elmira, N.Y., a corporation of Delaware Filed Dec. 16, 1964, Ser. No. 418,613 5 Claims. (Cl. 746) The present invention relates to engine starter gearing for an engine and more particularly, starter gearing of the positive shift type, including a dentil clutch to provide driving and overrunning and further including means for effecting the automatic separation of the clutch teeth after the engine becomes self-running.

The present invention is an improvement over the starter gearing system described in co-pending, commonlyassigned United States patent application Serial No. 269,434, entitled, Engine Starter Drive, filed April 1, 1963, now Patent No. 3,181,375, having as an inventor John J. Sabatini.

It is an object of the present invention to provide an improved starter drive of the type referenced, having automatic means for separating dentil clutch teeth after engine start-up which is reliable and relatively inexpensive to manufacture.

It is another object of the present invention to provide an improved starter drive having centrifugal weight and thrust washer means for separating dentil clutch teeth after engine start-up to prevent long periods of clutch over-running and accompanying deleterious wear.

It is a still further object of the present invention to provide an improved starter drive with centrifugal weight clutch separator means having means for mounting the centrifugal weights to avoid erratic action, to guard against dislodging the weights due to impact, to avoid inadevertent cocking of the weights while utilizing a form of construction adaptable to low cost manufacturing techniques.

Other objects and advantages Will become apparent on consideration of the accompanying description and drawmg.

Referring to the drawing, there is illustrated a starter drive for an engine generally designated by numeral 10, mounted on a power shaft 12 of a starting motor (not illustrated). The drive includes an axially-extending sleeve 14 connected to shaft 12 'by straight splines 16 so as to be axially, but not rotatively, movable relative to the shaft. The external surface of the forward or righthand extremity of the sleeve has helical splines 18 formed thereupon which a driving clutch member 20 is threaded and adapted for movement toward and away from a gear 22 of the engine to be started. The driving clutch member in its engaged position as illustrated, projects past the right end of sleeve 14 so that the right-most edge of the splines form a radially-inwardly-extending shoulder 24 for a purpose to be later described.

A pinion gear 26 is slidably journalled on bearing 63, which in turn, is mounted on a sleeve 28. Sleeve 28 is secured to sleeve 14 and is slidably supported on a reduced diameter extension of power shaft 12. The pinion gear is adapted for movement into and out of engagement with the engine gear 22. An annular driven clutch member 30 is integrally formed with the pinion gear as the left-most extension thereof, as illustrated in the drawings. The driven clutch member is formed to provide an annular or circular recess 32 radially inwardly of the clutch member having its inner extremity defined by sleeve 28.

The opposing or adjacent faces of the clutch members 20 and 30 are provided with complementing mutually engageable inclined torque transmitting dentil teeth 34 and 36, respectively. The dentils are of the saw-toothed variety to provide a one-way overrunning clutch connection.

A barrel-shaped housing 38, having a closed and an open end, is slidably supported at its closed end 40 on the external surface of sleeve 14. A lock ring 42 is seated in a notch adjacent the open end of the housing and has sufiicient radial length to engage driven clutch member 30 to thereby confine the clutch elements within the housing cavity.

The sleeve 14 is provided with a radial shoulder 44 intermediate its extremities to provide an abutment for a disc or washer 46 slidably journalled on the sleeve. A resiliently-yieldable cylinder 48, preferably of an elastically-deformable material, such as rubber, is compressively confined between the disc and closed housing end. A resilient spring member 50 is compressively confined between disc and driving clutch member to provide a biasing force, urging the clutches in an engaged position.

Means for moving the starter gear assembly toward or away from the engine gear 22 may comprise the conventional solenoid, air or hydraulic cylinder actuated lever, not illustrated, connected to the shift collar 52 which is connected to the closed end 40 of housing 38.

Means for accomplishing the automatic separation of dentil teeth 34 and 36 are arranged in the annular recess 32 within the driven clutch member 30. An annular thrust washer 54 backed by a loose thrust washer 67 abuts at its outer edge the shoulder 24 of driving clutch member 20. The radially-inner surface56 of the thrust washer is inclined or comically-formed with respect to the longitudinal axis of the starter gear. A plurality of arcuate centrifugal flyweight members are annularly arranged adjacent thrust washer 54, one such flyweight is designated by the numeral 58. Each flyweight has an inclined surface 60 complementary with and abutting surface 56 of the thrust washer. A radial hole 62 is formed in each weight at an intermediate or mid-point closely corresponding with the location of center of gravity of the weight member. A support pin 64 is secured on one end in a radial hole 66 formed in annular driven clutch member 30 and projects radially inwardly therefrom into the hole 62 in the fiyweight member. The pin and hole connection restrain the fiyweight from movement in either the axial or circumferential direction, While permitting radial movement in response to centrifugal force. It will be noted that sleeve bearing 63 projects into the annular recess 32 and provides a radially-inward stop for the flyweight 58, establishing clearance between fiyweight and sleeve 28 to avoid wear or snagging of the moving assembly.

In operation, when it is desired to crank the engine, the starter gearing assembly is shifted to the right via positioning mechanism connected to collar 52 and along the power shaft 12 so that pinion gear 26 engages engine starter gear 22. Shaft 12 is rotated by a starting motor and transmits torque through splines 16 to sleeve 14, from helical splines 18 to the driving clutch 20, driven clutch 30, pinion 26 to the engine gear. As the engine fires and becomes self-operating, engine gear 22 will now drive pinion 26 at a speed greater than that of the shaft 12. Clutch teeth 34 and 36 will slip so that the. starting motor is not driven at high engine speed. This condition formerly has caused severe wear of the dentil teeth where overrunning continues for prolonged periods as the relatively heavy clutch engagement spring 50 urges the clutch teeth towards the engaged position while the overrunning cam action between the teeth forces them apart. The result is clashing and severe impact on the teeth. In the present invention, however, as the engine accelerates, it will drive the fiyweights 58 through support pins 64, driven clutch 30, and pinion 26. The weights will tend to move radially outwardly, guided by pins 64 and will transmit axial thrust through the inclined surfaces 60 and 56 to the thrust washer or ring 54. Thrust washer 54 is urged to the left and through its abutting connection through loose washer 67 at shoulder 24 and will displace the driving clutch member 20 to the left against the biasing force of spring 50, causing separation of the clutch teeth at a predetermined engine self-operating speed. This action, of course, prevents the dentil teeth from being subject to long periods of contact while the pinion is overrunning.

The starter gearing is further designed to provide an indexing function should the pinion 26 abut one of the teeth of starter gear 22 when being actuated to the right into engagement. In such an event, pinion movement is obstructed by tooth abutment, but the shifting mechanism will continue to shift housing 38, sleeves 14 and 28. In an abutment, pinion and clutch stand still against ring gear while drive sleeves 14 and 28 and case 38 continue to shift rightwardly toward the ring gear. Thus, the pinion and clutch members will shift leftwardly relative to sleeve 14. Driving clutch 20 will be caused to rotate on helical splines 18 which rotation is transmitted to driven clutch 30 and pinion 26 through the dentil teeth so that the pinion will clear the obstructing tooth on engine gear 22. As the tooth is cleared, spring 50 snaps the pinion and clutch members to the right in the engaged position.

The starter gearing mechanism accomplishes all the normal functions of impact cushioning, indexing, overrunning, and in addition, provides automatic dentil tooth separation, greatly increasing starter gear life. Manufacturing is readily accomplished as the annular recess 32 is a simple cylindrical configuration and pin support holes are for-med by conventional drilling operation. The pin and hole mounting of weights 58 tends to prevent tipping of the weights as they fly outward and retains the weights in position so they cannot escape if the clutch members bounce apart due to impact during overrunning.

I claim:

1. Engine starter gearing comprising:

a power shaft;

a sleeve slidably, but non-rotatably, secured to said power shaft, said sleeve having external helical splines formed on one extremity thereof;

a pinion gear slidably jouma-lled for axial movement relative to the power shaft adapted for movement into and out of engagement with a gear of the engine to be started;

an annular driven clutch member secured to said pinion gear for movement therewith and forming a circular recess radially inwardly of said driven clutch memher;

a driving clutch member slidably mounted on said helical splines of said sleeve;

said driving and driven clutch members having complementary mutually-engagea'ble inclined teeth for transmitting torque therebetween in one direction of relative rotation;

a barrel housing having an open end, slidably supported on said sleeve and spatially encompassing said clutch members;

abutment means within the housing adjacent the open end thereof adapted for engagement with the driven clutch member for confining the clutch members within the housing;

resilient means within said housing abutting said driving clutch member and biasing said clutch members into engaged position;

said driving clutch member having a radially-inwardlyextending shoulder formed thereon adjacent said circular recess formed in said driven clutch member;

an annular thrust ring having an inner conical surface loosely disposed in said circular recess, said annular thrust ring adapted to abut said radially-inwardlyextending shoulder of said driving clutch member when displaced in a first axial direction;

a plurality of centrifugal fiyweight members annularly arranged within said circular recess, said fiyweight members each having an inclined surface abutting said conical surface of said thrust ring operative to displace said thrust ring in a first axial direction in response to centrifugal force;

a plurality of support pins, one for each fiyweight member connected to said driving clutch member and extending radially inward within said circular recess; and

each of said fiyweight members having a radiallyextending hole formed therein, connecting said weight members to respective support pins to prevent axial and permit radial movement of said fiyweight members.

2. Engine starter gearing as claimed in claim 1 wherein said radially-extending holes formed in said flyweight' members are formed at the approximate center of gravity of said weight members,

3. Engine starter gearing as claimed in claim 1 wherein said resilient means and said thrust ring apply opposed forces to said driving clutch member.

4. Engine starter gearing comprising:

a power shaft;

a sleeve slidably, but non-rotatably, secured to said power shaft, said sleeve having external helical splines formed on one extremity thereof;

a pinion gear slidably-journalled for axial movement relative to the power shaft adapted for movement into and out of engagement with a gear of the engine to be started;

an annular driven clutch member secured to said pinion gear for movement therewith and forming an annular Lecess radially inwardly of said driven clutch mem er;

a driving clutch member slidably mounted at one end on said helical splines of said sleeve;

said driving and driven clutch members having complementary mutually-engageable dentil teeth for transmitting torque therebetween;

a barrel housing having an open end, slidably supported on said sleeve and spatially encompassing said clutch members;

means within the housing adjacent the open end thereof adapted for engagement with the driven clutch member for confining the clutch members within the housing;

resilient means within said housing abutting said driving clutch member and biasing said clutch members into an engaged position wherein said driven clutch member engages said abutment means and said driving clutch member has an end extending off said sleeve member and adjacent said annular recess;

an annular thrust ring having an inner inclined surface loosely disposed in said circular recess and abutting the end of said driving clutch member extending off said sleeve member;

a plurality of arcuate centrifugal weight members annularly arranged within said annular recess, said weight members each having an inclined surface abutting said inclined surface of said thrust ring operative to displace said thrust ring and said driving 5 6 clutch member axially in response to centrifugal, driven clutch member to provide a radially inward abutthereby separating the dentil teeth of said clutch ment stop for said weight members. members at a predetermined rotational speed; and a plurality of radial support pins connected to said R f n e Ci d b the E i driving clutch member, one for each respective Weight 5 member to support said Weight members while per- UNITED STATES PATENTS mitting radial movement thereof in response to cen- '2554445 5/1951 Miner trifugal forces. 5. Engine starter gearing as claimed in claim 4, including stop means movable with said pinion gear and said 10 MILTON KAUFMAN Prlmmy Emmmw 

1. ENGINE STARTER GEARING COMPRISING: A POWER SHAFT; A SLEEVE SLIDABLY, BUT NON-ROTATABLY, SECURED TO SAID POWER SHAFT, SAID SLEEVE HAVING EXTERNAL HELICAL SPLINES FORMED ON ONE EXTREMITY THEREOF; A PINION GEAR SLIDABLY JOURNALLED FOR AXIAL MOVEMENT RELATIVE TO THE POWER SHAFT ADAPTED FOR MOVEMENT INTO AND OUT OF ENGAGEMENT WITH A GEAR OF THE ENGINE TO BE STARTED; AN ANNULAR DRIVEN CLUTCH MEMBER SECURED TO SAID PINION GEAR FOR MOVEMENT THEREWITH AND FORMING A CIRCULAR RECESS RADIALLY INWARDLY OF SAID DRIVEN CLUTCH MEMBER; A DRIVING CLUTCH MEMBER SLIDABLY MOUNTED ON SAID HELICAL SPLINES OF SAID SLEEVE; SAID DRIVING AND DRIVEN CLUTCH MEMBERS HAVING COMPLEMENTARY MUTUALLY-ENGAGEABLE INCLINED TEETH FOR TRANSMITTNG TORQUE THEREBETWEEN IN ONE DIRECTION OF RELATIVE ROTATION; A BARREL HOUSING HAVING AN OPEN END, SLIDABLY SUPPORTED ON SAID SLEEVE AND SPATIALLY ENCOMPASSING SAID CLUTCH MEMBERS; ABUTMENT MEANS WITHIN THE HOUSING ADJACENT THE OPEN END THEREOF ADAPTED FOR ENGAGEMENT WITH THE DRIVEN CLUTCH MEMBER FOR CONFINING THE CLUTCH MEMBERS WITHIN THE HOUSING; RESILIENT MEANS WITHIN SAID HOUSING ABUTTING SAID DRIVING CLUTCH MEMBER AND BIASING SAID CLUTCH MEMBERS INTO ENGAGED POSITION; SAID DRIVING CLUTCH MEMBER HAVING A RADIALLY-INWARDLYEXTENDING SHOULDER FORMED THEREON ADJACENT SAID CIRCULAR RECESS FORMED IN SAID DRIVEN CLUTCH MEMBER; AND ANNULAR THRUST RING HAVING AN INNER CONICAL SURFACE LOOSELY DISPOSED IN SAID CIRCULAR RECESS, SAID ANNULAR THRUST RING ADAPTED TO ABUT SAID RADIALLY-INWARDLYEXTENDING SHOULDER OF SAID DRIVING CLUTCH MEMBER WHEN DISPLACED IN A FIRST AXIAL DIRECTION; A PLURALITY OF CENTRIFUGAL FLYWEIGHT MEMBERS ANNULARLY ARRANGED WITHIN SAID CIRCULAR RECESS, SAID FLYWEIGHT MEMBERS EACH HAVING AN INCLINED SURFACE ABUTTING SAID CONICAL SURFACE OF SAID THRUST RING OPERATIVE TO DISPLACE SAID THRUST RING IN A FIRST AXIAL DIRECTION IN RESPONSE TO CENTRIFUGAL FORCE; A PLURALITY OF SUPPORT PINS, ONE FOR EACH FLYWEIGHT MEMBER CONNECTED TO SAID DRIVING CLUTCH MEMBER AND EXTENDING RADIALLY INWARD WITHIN SAID CIRCULAR RECESS; AND EACH OF SAID FLYWEIGHT MEMBERS HAVING A RADIALLYEXTENDING HOLE FORMED THEREIN, CONNECTING SAID WEIGHT MEMBERS TO RESPECTIVE SUPPORT PINS TO PREVENT AXIAL AND PERMIT RADIAL MOVEMENT OF SAID FLYWEIGHT MEMBERS. 